Electronic Components
Series Inductor Calculator
The purpose of Series Inductor is to turn inductor L1 and inductor L2 into equivalent inductance. Keep the source condition with the saved result so later comparisons remain meaningful.
Enter values for Equivalent inductance
Use measurements from one operating condition.
How the result is calculated
Start with the equation Leq = L1 + L2. The formula draws on Inductor L1 and Inductor L2.
Using the loaded examples gives 32.00 mH. Your saved case should identify where each entry came from.
Calculate equivalent inductance from inductor L1 and inductor L2. For the companion equivalent inductance calculation, open Parallel Inductor Calculator.
Sensitivity check
Change Inductor L1 from 10 mH to 12 mH and leave all other entries untouched. The displayed value changes from 32.00 mH to 34.00 mH.
Keep both cases when the changed input represents genuine uncertainty.
Values this page needs
Record tolerance, bias point, duty cycle, and junction temperature. If operating conditions changed between readings, calculate separate cases.
Use the displayed unit for every field and document conversions separately.
- Inductor L1
- Default example: 10 mH. Enter inductor L1 in mH.
- Inductor L2
- Default example: 22 mH. Enter inductor L2 in mH.
Checks that catch bad inputs
Unit-prefix mistakes often dominate the arithmetic error.
Check the input source before adding a safety or correction factor.
Reading Equivalent inductance
Read Equivalent inductance as the outcome of this equation, not as automatic equipment approval. Compare it with the selected component data-sheet limits.
Label alternate cases rather than overwriting the baseline.
What the formula leaves out
Mutual coupling is assumed negligible.
Additional checks may be needed for pulse ratings, frequency behavior, package temperature, and layout. Document which effects were checked elsewhere in the analysis.
Use data-sheet values at the intended voltage, current, frequency, and temperature.
Review the case step by step
Begin by confirming inductor L1 at the operating point represented by the other entries. Record whether it came from a meter, nameplate, data sheet, or design assumption.
After calculating equivalent inductance, compare its magnitude with voltage rating, current rating, dissipation, tolerance, and transient stress. An independent order-of-magnitude check can reveal a misplaced decimal or unit prefix.
Document any effect handled outside this page, especially bias dependence, ESR, leakage, saturation, and self-heating. That note prevents a later reader from assuming the simple equation covered it.
Questions from practical use
Why might a second instrument give another answer?
Recheck units and operating state before investigating parasitics, layout inductance, tolerance stack-up, switching edges, and thermal resistance.
Can I change several inputs at once?
Keep unaffected entries fixed so the cause of the difference remains visible. Keep nominal component markings separate from measured operating values.
Does Series Inductor Calculator choose a final rating?
Use the number as one check, then review the selected component data-sheet limits.
What precision should move to the next worksheet?
Keep full precision while transferring equivalent inductance; round only at the final reporting or selection step.
Can zero describe the baseline case?
Leave the case unfinished until the real value is known rather than entering a placeholder zero.